1. Field of the Invention
The present invention relates to a communication card provided with a communication circuit.
2. Description of the Prior Art
Lately communication cards each of which is provided with a communication circuit have widely been used for input/output control of transmitting and receiving signals between transmitting and receiving units such as personal computers, word processors and other computers and communication lines such as telephone lines. One of these communication cards is known as a modem card, which is adapted to convert digital signals to be transmitted from a transmitter/receiver equipment to analog signals and transmit these analog signals through a communication line and, in turn, convert analog signals transmitted from the transmission line to digital signals and send these digital signals to the transmitter/receiver eqipment. This modem card is inserted as specified into a slot provided at the transmitter/receiver equipment and electrically connected to the equipment and, in addition, the transmitter/receiver equipment and the communication line are electrically connected through the communication circuit of the comminication card by reconnectably connecting a cord of the communication line such as the telephone line to the modem card to permit communication between personal computers.
An example of a modem card as well as a telephone line cord according to the prior art is shown in FIG. 1. In FIG. 1, a connector part of 14 mm in thickness is built in a rear end side of a modem card of approximately 5 mm in thickness and a modular fitting hole 20 for fitting a modular plug 2 provided at an extreme end of a cord 21 is formed in a connector part 23.
The modular plug 2 is provided with a lug 25 which is slantly protruded above a housing 24 as shown in FIGS. 11A, 11B and 11C and hooks 26 for preventing returning movement are provided as being protruded at both sides of the base of the lug 25. When the front end part of the lug 25 and a bottom of a housing 24 are held by fingers and a force is applied thereto, the lug is moved in a direction indicated with an arrow toward the upper surface 15 of the housing 24 as shown in FIG. 11A, comes in a state as shown in FIG. 11B and, when the fingers are released, the lug returns to its original position. A protruded part 27 which is protruded more than the front end face 28 of the housing 24 is provided on the upper front end part of the housing 24, a cord insertion hole (not shown) is formed at the rear end side of the housing 24, the cord 21 is inserted into the cord insertion hole, and four lead wires (not shown) extended from the cord 21 are arranged in the housing 24.
As shown in FIG. 3, six terminal accommodating slots 29 are formed at the bottom part of the housing 24 and terminals 30 are accommodated in four terminal accommodating slots 29 except for terminal accommodating slots 29 at both end sides, terminals 30 being electrically connected to the lead wires extended from the cord 21.
As shown in FIG. 2, the modular fitting hole 20 formed in the connector 23 of the modem card 1 is provided with an internal wall part 4 of the connector 23 which functions as a guide for setting an inserting direction of the modular plug 2, so that the modular plug 2 can be inserted into the inlet port through to the inner part of the modular fitting hole 20 along this internal wall part 4.
As shown in FIG. 4B, an extreme end position setting part 5 for positioning the extreme end of the modular plug 2, which is inserted into the inner part of the modular fitting hole 20 is provided. When the modular plug 2 shown in FIG. 4A is moved in an arrow direction and inserted into the modular fitting hole 20 of the connector 23 shown in FIG. 4B, the protruded part 27 of the modular plug 2 comes in contact with the extreme end position setting part 5 to prevent the modular plug 2 from advancing more.
A return prevention part 6 for engaging with the modular plug 2 inserted to prevent the modular plug 2 from coming off is provided at the upper part of the inlet port of the modular fitting hole 20, and the rear end part of the hook 26 of the modular plug 2 engages with the return prevention part 6 shortly before the protruded part 27 of the modular plug 2, which is inserted into the inner part of the modular fitting hole 20, comes in contact with the extreme end position setting part 5 of the modular fitting hole 20 whereby the modular plug 2 returns to the inlet port 22 of the modular fitting hole 20 and the modular plug 2 is prevented from coming off from the modular fitting hole 20.
For removing the modular plug 2 from the modular fitting hole 20, the lug 25 of the modular plug 2, which is protruded out of the modular fitting hole 20, is pushed down by a finger to approach the upper surface 15 of the housing 24 as shown in FIG. 4C and the hook 26 is kept released from the return prevention part 6 whereby the modular plug 2 can be removed from the modular fitting hole 20.
As shown in FIG. 2, six terminal accommodating slots 18 are formed at the lower part of the modular fitting hole 20 and the front end parts of connection terminals 8 are connected to four terminal accommodating slots 18 except the terminal accommodating slots 18 at both side ends whereby the arranging area of these connection terminals 8 functions as a terminal connecting part to be electrically connected with terminals 30 of the modular plug 2.
The modem card formed as described above is inserted from its front end into the slot of the personal computer as described above and the modular plug 2 at the extreme end side of the cord 21 is inserted into the connector part 23 at the rear end side of the card as shown in FIG. 1.
However, there has been a problem that, when the modem card 1 was set in the personal computer, the connector 23 at the rear end part of the modem card 1 protrudes from the body of the personal computer and the thick connector 23 which protrudes from the body of the personal computer or the like would be obstructive. In most cases, the personal computer has been moved with the modem card 1 kept inserted into the personal computer after disconnecting the modular plug 2 from the connector part 23 and therefore there has been a problem that the thick connector part 23 protruding out of the personal computer body might be struck with a desk or the like to cause the modem card 1 and the personal computer body to malfunction.
In addition, there has been a problem, if the rear end part of the modem card 1 is made to be thick to provide the connector part 23 in making the modem card 1, costs of materials and the modem card would be more expensive.
This type of modem card includes a problem that it is difficult to determine a position for inserting the modular plug into the modem card and therefore the modular plug may be erroneously inserted.